Common Pacing Mistakes
The number one pacing mistake is starting too fast, driven by race-day adrenaline and the crowd energy at the start line. Studies of major marathon events show that 70–80% of recreational runners start their first kilometre faster than their average pace — and those who do are significantly more likely to hit the wall after 30K. The second most common error is neglecting the course profile: running even splits on a hilly course means running too hard on uphills and not fast enough on downhills. Instead, target even effort — slow down on uphills (add 10–15 seconds per kilometre per 2% gradient) and accelerate slightly on downhills. A third mistake is changing strategy mid-race based on how you feel at halfway. Feeling good at 21K in a marathon doesn't mean you should speed up — glycogen depletion and muscle damage accumulate non-linearly, and the second half will always feel harder than the first. Trust your pre-race plan and the split targets you set with tools like this calculator. For wheelchair racers, drafting dynamics can significantly affect split strategy, especially in road marathons where drafting behind other chairs reduces air resistance by 20–30%.
How to Plan Your Race Splits
A split is your time for each km or mile segment during a race. Planning splits in advance helps you pace evenly and avoid blowing up in the second half.
Negative Splits — The Gold Standard
Running the second half of a race slightly faster than the first is the most efficient strategy. It conserves glycogen early and lets you pick up speed when others fade.
Even Splits
Running exactly the same pace throughout requires discipline but is very effective. Most world records are set with near-even splits.
Positive Splits — What to Avoid
Going out too fast feels easy in the first kilometres but leads to a painful second half. If you find yourself running positive splits consistently, try starting 10–15 seconds per km slower.